Comment 10 for bug 599394

For posterity: I believe this to be a bug in debootstrap that was caused by an update to the ubuntu-keyring package [1] that received no corresponding update to the debootstrap 'configuration' files [2].

To summarize:

- This affects Ubuntu <= 12.04 chroots on Ubuntu >= 17.04 hosts.
- The best workaround that I know of is the following command:

sudo debootstrap --keyring=/usr/share/keyrings/ubuntu-archive-removed-keys.gpg precise /tmp/precise http://old-releases.ubuntu.com/ubuntu/

The important bit is the non-default --keyring argument.

[1] https://bugs.launchpad.net/ubuntu/+source/ubuntu-keyring/+bug/1363482
[2] https://bugs.launchpad.net/ubuntu/+source/ubuntu-keyring/+bug/1363482/comments/7